Stainless Steel PH13-8Mo (XM-13 / UNS S13800)

PH13-8Mo is a premium precipitation-hardening stainless steel developed to provide a superior combination of strength, toughness, weldability, and corrosion resistance. The alloy derives its high mechanical properties from a martensitic matrix strengthened by finely dispersed precipitates formed during aging treatment.

Compared with conventional stainless steels and many PH grades, PH13-8Mo offers excellent transverse toughness, reduced segregation, and improved mechanical property consistency, making it highly desirable for aerospace and critical engineering applications.

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PH13-8Mo At a Glance

Key Attribute	Value
Material	PH13-8Mo Stainless Steel
UNS Number	S13800
Common Name	XM-13 / 13-8 PH
Material Type	Precipitation Hardening Stainless Steel
Structure	Martensitic PH Stainless Steel
Density	7.76 g/cm³
Main Strengthening Method	Precipitation Hardening
Tensile Strength	Up to 1,550 MPa
Main Advantage	Ultra-High Strength & Toughness
Typical Industries	Aerospace, Nuclear, Defense, Energy

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Features of PH13-8Mo

• Exceptional strength-to-weight ratio
• Excellent fracture toughness
• Superior transverse toughness
• Outstanding stress corrosion cracking resistance
• Excellent fatigue resistance
• Good weldability
• Uniform mechanical properties
• High hardness capability after aging
• Good corrosion resistance in industrial environments
• Excellent dimensional stability during heat treatment

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Chemical Composition of PH13-8Mo

Element	Content (%)
Chromium (Cr)	12.25 – 13.25
Nickel (Ni)	7.50 – 8.50
Molybdenum (Mo)	2.00 – 2.50
Aluminum (Al)	0.90 – 1.35
Manganese (Mn)	≤ 0.10
Silicon (Si)	≤ 0.10
Carbon (C)	≤ 0.05
Phosphorus (P)	≤ 0.01
Sulfur (S)	≤ 0.008
Iron (Fe)	Balance

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Physical Properties of PH13-8Mo

Property	Value
Density	7.76 g/cm³
Melting Range	1404 – 1454°C
Electrical Resistivity	0.80 μΩ·m
Thermal Conductivity	18.6 W/m·K
Specific Heat Capacity	460 J/kg·K
Modulus of Elasticity	196 GPa

Mechanical Properties of PH13-8Mo

Aged Condition Typical Values

Property	Typical Value
Tensile Strength	1,350 – 1,550 MPa
Yield Strength (0.2%)	1,200 – 1,450 MPa
Elongation	10 – 15%
Hardness	38 – 45 HRC

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Corrosion Resistance

PH13-8Mo provides corrosion resistance superior to many high-strength alloy steels and comparable to 17-4PH in many environments.

It offers:

• Good atmospheric corrosion resistance
• Good marine atmosphere resistance
• Excellent stress corrosion cracking resistance
• Good resistance to industrial chemicals
• Improved resistance to hydrogen embrittlement
• Excellent corrosion-fatigue performance

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High Temperature Performance

PH13-8Mo is primarily designed for high-strength structural applications rather than prolonged elevated-temperature exposure.

Recommended Service Temperature

• Cryogenic temperatures
• Ambient temperatures
• Up to approximately 315°C (600°F)

Above this range, over-aging may reduce strength.

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Available Forms

J&A Alloy supplies PH13-8Mo in:

• Round Bar
• Forged Bar
• Plate
• Sheet
• Billet
• Block
• Ring Forgings
• Wire
• Tube
• Custom Machined Parts

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Applications of PH13-8Mo

Aerospace

• Aircraft structural components
• Landing gear components
• Fasteners
• Engine hardware

Defense

• Missile components
• Weapon systems
• Armor support structures

Energy

• Nuclear reactor components
• High-pressure equipment

Industrial

• Valve stems
• Pump shafts
• Tooling components

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PH13-8Mo vs Other PH Stainless Steels

Grade	Strength	Toughness	Main Advantage
PH13-8Mo	Excellent	Excellent	Best Strength/Toughness Balance
17-4PH	Very Good	Good	General Purpose PH Grade
15-5PH	Very Good	Very Good	Aerospace Applications
A286	High	Good	Higher Temperature Capability

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Welding & Fabrication

Welding

Recommended processes:

• GTAW (TIG)
• GMAW (MIG)
• Resistance Welding
• Laser Welding

Heat Treatment

Solution Treatment:
927 – 954°C

Air Cool

Age Hardening:
510 – 593°C

Machining

PH13-8Mo machines well in the solution-treated condition and develops maximum strength after aging.

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Standards & Equivalent Grades

Standard	Designation
UNS	S13800
AISI	XM-13
Common Name	13-8 PH
AMS	5629
ASTM Bar	A564 Type XM-13
ASTM Plate	A693 XM-13

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Frequently Asked Questions

What is PH13-8Mo stainless steel?

PH13-8Mo is a martensitic precipitation-hardening stainless steel known for exceptional strength, toughness, and corrosion resistance.

What is the UNS designation of PH13-8Mo?

UNS S13800.

Is PH13-8Mo stronger than 17-4PH?

Yes. PH13-8Mo generally provides higher toughness and higher achievable strength levels.

What is XM-13 stainless steel?

XM-13 is the AISI designation for PH13-8Mo stainless steel.

Can PH13-8Mo be welded?

Yes. It has excellent weldability and is commonly welded in aerospace applications.

What industries use PH13-8Mo?

Aerospace, defense, nuclear, energy, and high-performance engineering industries.

Is PH13-8Mo corrosion resistant?

Yes. It offers excellent resistance to atmospheric corrosion and stress corrosion cracking.

What forms are available?

Bar, plate, sheet, forgings, wire, rings, billets, and machined components.

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Why Choose J&A Alloy

PH Stainless Steel Expertise

Specialized supplier of precipitation-hardening stainless steels and aerospace alloys.

Comprehensive Quality Control

• PMI Testing
• Chemical Analysis
• Mechanical Testing
• Hardness Testing
• Ultrasonic Inspection

International Standards Compliance

• AMS Standards
• ASTM Standards
• EN 10204 3.1 Certification
• Third-Party Inspection Available

Advanced Processing Services

• Precision Machining
• Forging
• Heat Treatment
• Custom Manufacturing

Global Aerospace Supply Experience

Trusted supplier for aerospace, defense, nuclear, and industrial engineering sectors worldwide.